Adding tasks to SO's for restricted users

[joebordes]

Tasks was already there, it is the block right above the first one added in the patch above:

https://github.com/tsolucio/corebos/blob/8bee33e8676177e3863f84ed755642775c898ecf/modules/SalesOrder/SalesOrder.php#L190

if the current user has permission to access the "parent_id" field on Calendar module they will see the "Add Task" button. I tried this with both admin and normal user in my development install and it is there.